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Arma Internasional, 2004
Buku Teks
Biringer, Betty E.
John Wiley & Sons, 2007
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Wheeler, James E.
Richard D. Irwin , 1981
Buku Teks
Springer Wiesbaden, 2023
eBooks
American Psychological Association, {s.a}
Majalah, Jurnal, Buletin